The present invention relates generally to tracheostomy tubes and relates more specifically to talking tracheostomy tubes.
Whenever a patient is placed on a ventilator, it is with an obligate loss of speech. This loss of speech may result in great fear, frustration and withdrawal of the ventilated patient. Many techniques of communication have been substituted for speech in an effort to alleviate anxiety of the patient and to facilitate health care delivery. These substitutes include lip reading, writing and the use of hand signals. Unfortunately, few hospital staff are able to lip read, writing is cumbersome, and many times the ventilated patient lacks the strength or ability to comply as is the case with hand signals. Speech with the electrolarynx has also been used. However the electrolarynx takes some time to master and the paralyzed patient finds its use nearly impossible.
Other methods to communicate with patients ventilated via a tracheostomy have involved laryngeal speech. Laryngeal speech has been accomplished in three ways. First the cuff of the tracheostomy tube has been partially deflated allowing a minimal air leak around the cuff and through the larynx during the lung filling phase of ventilation. Although this techique does result in speech, the speech is intermittent, dependent on the respirator cycle, does not allow measurement of tidal volumes, and may result in aspiration.
Another method of speech is with a valved, fenestrated tracheostomy tube. The tracheostomy tube used may be equipped with a ventilator activated valve that directs air through a fenestration in the tracheostomy tube and through the larynx during the expiratory phase of ventilation. This method, again, is intermittent, dependent on the phase of the respirator, does not allow measurement of air return during speech, may result in aspiration during the expiration phase, and often could only be used with a Bird respirator for which it was designed.
Another method of speech involves attaching a catheter "piggy-back" along the length of a tracheostomy tube nearly to the cuff. This catheter was then connected to an air or oxygen source. With the tracheostomy tube and catheter in place, air or oxygen travels via the catheter through the stoma along the length of the tracheostomy tube. The air or oxygen may then be released into the trachea superior to the cuff where it flows through the larynx and out the pharynx. In addition to the production of laryngeal speech, this technique may be used with any respirator, speech may be uninterrupted, speech may be independent of the respirator phase, exact tidal measurements can be made, there are no moving parts, and finally there is substantially no chance of aspiration during any phase of respiration.
However, prior to the present invention, existing "piggy-back" type tracheostomy tubes have encountered the same difficulties of those in the past. That is, they may produce discomfort at high air flows through the larynx (i.e. greater than 5 liters/minute) which may be necessary to produce speech. In addition, leakage of air around the stoma was encountered as was subcutaneous emphysema.